Redflag/aggregator-agent/internal/migration/executor.go

package migration

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"time"
)

// MigrationPlan represents a complete migration plan
type MigrationPlan struct {
	Detection            *MigrationDetection `json:"detection"`
	TargetVersion        string              `json:"target_version"`
	Config               *FileDetectionConfig `json:"config"`
	BackupPath           string              `json:"backup_path"`
	EstimatedDuration    time.Duration       `json:"estimated_duration"`
	RiskLevel            string              `json:"risk_level"` // low, medium, high
}

// MigrationResult represents the result of a migration execution
type MigrationResult struct {
	Success        bool          `json:"success"`
	StartTime      time.Time     `json:"start_time"`
	EndTime        time.Time     `json:"end_time"`
	Duration       time.Duration `json:"duration"`
	BackupPath     string        `json:"backup_path"`
	MigratedFiles  []string      `json:"migrated_files"`
	Errors         []string      `json:"errors"`
	Warnings       []string      `json:"warnings"`
	AppliedChanges []string      `json:"applied_changes"`
	RollbackAvailable bool       `json:"rollback_available"`
}

// MigrationExecutor handles the execution of migration plans
type MigrationExecutor struct {
	plan   *MigrationPlan
	result *MigrationResult
}

// NewMigrationExecutor creates a new migration executor
func NewMigrationExecutor(plan *MigrationPlan) *MigrationExecutor {
	return &MigrationExecutor{
		plan:   plan,
		result: &MigrationResult{},
	}
}

// ExecuteMigration executes the complete migration plan
func (e *MigrationExecutor) ExecuteMigration() (*MigrationResult, error) {
	e.result.StartTime = time.Now()
	e.result.BackupPath = e.plan.BackupPath

	fmt.Printf("[MIGRATION] Starting migration from %s to %s\n",
		e.plan.Detection.CurrentAgentVersion, e.plan.TargetVersion)

	// Phase 1: Create backups
	if err := e.createBackups(); err != nil {
		return e.completeMigration(false, fmt.Errorf("backup creation failed: %w", err))
	}
	e.result.AppliedChanges = append(e.result.AppliedChanges, "Created backups at "+e.plan.BackupPath)

	// Phase 2: Directory migration
	if contains(e.plan.Detection.RequiredMigrations, "directory_migration") {
		if err := e.migrateDirectories(); err != nil {
			return e.completeMigration(false, fmt.Errorf("directory migration failed: %w", err))
		}
		e.result.AppliedChanges = append(e.result.AppliedChanges, "Migrated directories")
	}

	// Phase 3: Configuration migration
	if contains(e.plan.Detection.RequiredMigrations, "config_migration") {
		if err := e.migrateConfiguration(); err != nil {
			return e.completeMigration(false, fmt.Errorf("configuration migration failed: %w", err))
		}
		e.result.AppliedChanges = append(e.result.AppliedChanges, "Migrated configuration")
	}

	// Phase 4: Security hardening
	if contains(e.plan.Detection.RequiredMigrations, "security_hardening") {
		if err := e.applySecurityHardening(); err != nil {
			e.result.Warnings = append(e.result.Warnings,
				fmt.Sprintf("Security hardening incomplete: %v", err))
		} else {
			e.result.AppliedChanges = append(e.result.AppliedChanges, "Applied security hardening")
		}
	}

	// Phase 5: Validation
	if err := e.validateMigration(); err != nil {
		return e.completeMigration(false, fmt.Errorf("migration validation failed: %w", err))
	}

	return e.completeMigration(true, nil)
}

// createBackups creates backups of all existing files
func (e *MigrationExecutor) createBackups() error {
	backupPath := e.plan.BackupPath
	if backupPath == "" {
		timestamp := time.Now().Format("2006-01-02-150405")
		backupPath = fmt.Sprintf(e.plan.Config.BackupDirPattern, timestamp)
		e.plan.BackupPath = backupPath
	}

	fmt.Printf("[MIGRATION] Creating backup at: %s\n", backupPath)

	// Create backup directory
	if err := os.MkdirAll(backupPath, 0755); err != nil {
		return fmt.Errorf("failed to create backup directory: %w", err)
	}

	// Backup all files in inventory
	allFiles := e.collectAllFiles()
	for _, file := range allFiles {
		if err := e.backupFile(file, backupPath); err != nil {
			return fmt.Errorf("failed to backup file %s: %w", file.Path, err)
		}
		e.result.MigratedFiles = append(e.result.MigratedFiles, file.Path)
	}

	return nil
}

// migrateDirectories handles directory migration from old to new paths
func (e *MigrationExecutor) migrateDirectories() error {
	fmt.Printf("[MIGRATION] Migrating directories...\n")

	// Create new directories
	newDirectories := []string{e.plan.Config.NewConfigPath, e.plan.Config.NewStatePath}
	for _, newPath := range newDirectories {
		if err := os.MkdirAll(newPath, 0755); err != nil {
			return fmt.Errorf("failed to create directory %s: %w", newPath, err)
		}
		fmt.Printf("[MIGRATION] Created directory: %s\n", newPath)
	}

	// Migrate files from old to new directories
	for _, oldDir := range e.plan.Detection.Inventory.OldDirectoryPaths {
		newDir := e.getNewDirectoryPath(oldDir)
		if newDir == "" {
			continue
		}

		if err := e.migrateDirectoryContents(oldDir, newDir); err != nil {
			return fmt.Errorf("failed to migrate directory %s to %s: %w", oldDir, newDir, err)
		}
		fmt.Printf("[MIGRATION] Migrated: %s → %s\n", oldDir, newDir)
	}

	return nil
}

// migrateConfiguration handles configuration file migration
func (e *MigrationExecutor) migrateConfiguration() error {
	fmt.Printf("[MIGRATION] Migrating configuration...\n")

	// Find and migrate config files
	for _, configFile := range e.plan.Detection.Inventory.ConfigFiles {
		if strings.Contains(configFile.Path, "config.json") {
			newPath := e.getNewConfigPath(configFile.Path)
			if newPath != "" && newPath != configFile.Path {
				if err := e.migrateConfigFile(configFile.Path, newPath); err != nil {
					return fmt.Errorf("failed to migrate config file: %w", err)
				}
				fmt.Printf("[MIGRATION] Migrated config: %s → %s\n", configFile.Path, newPath)
			}
		}
	}

	return nil
}

// applySecurityHardening applies security-related configurations
func (e *MigrationExecutor) applySecurityHardening() error {
	fmt.Printf("[MIGRATION] Applying security hardening...\n")

	// This would integrate with the config system to apply security defaults
	// For now, just log what would be applied

	for _, feature := range e.plan.Detection.MissingSecurityFeatures {
		switch feature {
		case "nonce_validation":
			fmt.Printf("[MIGRATION] Enabling nonce validation\n")
		case "machine_id_binding":
			fmt.Printf("[MIGRATION] Configuring machine ID binding\n")
		case "ed25519_verification":
			fmt.Printf("[MIGRATION] Enabling Ed25519 verification\n")
		case "subsystem_configuration":
			fmt.Printf("[MIGRATION] Adding missing subsystem configurations\n")
		case "system_subsystem":
			fmt.Printf("[MIGRATION] Adding system scanner configuration\n")
		case "updates_subsystem":
			fmt.Printf("[MIGRATION] Adding updates subsystem configuration\n")
		}
	}

	return nil
}

// validateMigration validates that the migration was successful
func (e *MigrationExecutor) validateMigration() error {
	fmt.Printf("[MIGRATION] Validating migration...\n")

	// Check that new directories exist
	newDirectories := []string{e.plan.Config.NewConfigPath, e.plan.Config.NewStatePath}
	for _, newDir := range newDirectories {
		if _, err := os.Stat(newDir); err != nil {
			return fmt.Errorf("new directory %s not found: %w", newDir, err)
		}
	}

	// Check that config files exist in new location
	for _, configFile := range e.plan.Detection.Inventory.ConfigFiles {
		newPath := e.getNewConfigPath(configFile.Path)
		if newPath != "" {
			if _, err := os.Stat(newPath); err != nil {
				return fmt.Errorf("migrated config file %s not found: %w", newPath, err)
			}
		}
	}

	fmt.Printf("[MIGRATION] ✅ Migration validation successful\n")
	return nil
}

// Helper methods

func (e *MigrationExecutor) collectAllFiles() []AgentFile {
	var allFiles []AgentFile
	allFiles = append(allFiles, e.plan.Detection.Inventory.ConfigFiles...)
	allFiles = append(allFiles, e.plan.Detection.Inventory.StateFiles...)
	allFiles = append(allFiles, e.plan.Detection.Inventory.BinaryFiles...)
	allFiles = append(allFiles, e.plan.Detection.Inventory.LogFiles...)
	allFiles = append(allFiles, e.plan.Detection.Inventory.CertificateFiles...)
	return allFiles
}

func (e *MigrationExecutor) backupFile(file AgentFile, backupPath string) error {
	relPath, err := filepath.Rel(e.plan.Config.OldConfigPath, file.Path)
	if err != nil {
		// Try relative to old state path
		relPath, err = filepath.Rel(e.plan.Config.OldStatePath, file.Path)
		if err != nil {
			relPath = filepath.Base(file.Path)
		}
	}

	backupFilePath := filepath.Join(backupPath, relPath)
	backupDir := filepath.Dir(backupFilePath)

	if err := os.MkdirAll(backupDir, 0755); err != nil {
		return fmt.Errorf("failed to create backup directory: %w", err)
	}

	// Copy file to backup location
	if err := copyFile(file.Path, backupFilePath); err != nil {
		return fmt.Errorf("failed to copy file to backup: %w", err)
	}

	return nil
}

func (e *MigrationExecutor) migrateDirectoryContents(oldDir, newDir string) error {
	return filepath.Walk(oldDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		if info.IsDir() {
			return nil
		}

		relPath, err := filepath.Rel(oldDir, path)
		if err != nil {
			return err
		}

		newPath := filepath.Join(newDir, relPath)
		newDirPath := filepath.Dir(newPath)

		if err := os.MkdirAll(newDirPath, 0755); err != nil {
			return fmt.Errorf("failed to create directory: %w", err)
		}

		if err := copyFile(path, newPath); err != nil {
			return fmt.Errorf("failed to copy file: %w", err)
		}

		return nil
	})
}

func (e *MigrationExecutor) migrateConfigFile(oldPath, newPath string) error {
	// This would use the config migration logic from the config package
	// For now, just copy the file
	return copyFile(oldPath, newPath)
}

func (e *MigrationExecutor) getNewDirectoryPath(oldPath string) string {
	if oldPath == e.plan.Config.OldConfigPath {
		return e.plan.Config.NewConfigPath
	}
	if oldPath == e.plan.Config.OldStatePath {
		return e.plan.Config.NewStatePath
	}
	return ""
}

func (e *MigrationExecutor) getNewConfigPath(oldPath string) string {
	if strings.HasPrefix(oldPath, e.plan.Config.OldConfigPath) {
		relPath := strings.TrimPrefix(oldPath, e.plan.Config.OldConfigPath)
		return filepath.Join(e.plan.Config.NewConfigPath, relPath)
	}
	if strings.HasPrefix(oldPath, e.plan.Config.OldStatePath) {
		relPath := strings.TrimPrefix(oldPath, e.plan.Config.OldStatePath)
		return filepath.Join(e.plan.Config.NewStatePath, relPath)
	}
	return ""
}

func (e *MigrationExecutor) completeMigration(success bool, err error) (*MigrationResult, error) {
	e.result.EndTime = time.Now()
	e.result.Duration = e.result.EndTime.Sub(e.result.StartTime)
	e.result.Success = success
	e.result.RollbackAvailable = success && e.result.BackupPath != ""

	if err != nil {
		e.result.Errors = append(e.result.Errors, err.Error())
	}

	if success {
		fmt.Printf("[MIGRATION] ✅ Migration completed successfully in %v\n", e.result.Duration)
		if e.result.RollbackAvailable {
			fmt.Printf("[MIGRATION] 📦 Rollback available at: %s\n", e.result.BackupPath)
		}
	} else {
		fmt.Printf("[MIGRATION] ❌ Migration failed after %v\n", e.result.Duration)
		if len(e.result.Errors) > 0 {
			for _, errMsg := range e.result.Errors {
				fmt.Printf("[MIGRATION] Error: %s\n", errMsg)
			}
		}
	}

	return e.result, err
}

// Utility functions

func contains(slice []string, item string) bool {
	for _, s := range slice {
		if s == item {
			return true
		}
	}
	return false
}

func copyFile(src, dst string) error {
	sourceFile, err := os.Open(src)
	if err != nil {
		return err
	}
	defer sourceFile.Close()

	destFile, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer destFile.Close()

	_, err = destFile.ReadFrom(sourceFile)
	if err != nil {
		return err
	}

	// Preserve file permissions
	sourceInfo, err := os.Stat(src)
	if err != nil {
		return err
	}

	return os.Chmod(dst, sourceInfo.Mode())
}